Of course. However, the sex isn't designed to make people think, "Oh, this product comes with a free slut, I'll buy it," it's more designed to make people remember the product. An example is an ad campaign for turning out lights called "Flick Off," where the tagline would momentarily flash on the screen, in all caps, with the L slightly rounded and right up close to the I. It looked like "Fuck Off," and I still remember it after a few years. The raciness makes the product stick in one's mind and therefore more likely to jump out at you when you're browsing the shelves at your local shopping centre.
And on Megan Fox: I find it pathetically tragic that people flock to her movies. She's not going to appear naked, and the money to buy tickets, popcorn, some twizzlers, and a drink could all be spent more effectively on taking a nice girl out to dinner or something so that you can maybe form a meaningful relationship with a human being whose company you genuinely enjoy. I think it's called "courting."